1. Field of the Invention
The present invention relates to a radio-controlled timepiece and to a control method for a radio-controlled timepiece.
2. Description of the Related Art
Radio-controlled timepieces that receive a longwave standard radio signal with superposed time information and automatically adjust the time based on the received signal are known. See particularly Japanese Patent 2973303, paragraphs [0022] to [0027]. In addition to forced reception, which is activated by the user operating the crown or a button to force the timepiece to receive the standard radio signal, this radio-controlled timepiece also has an automatic reception mode in which the timepiece automatically receives the standard time signal at a preset reception time and automatically adjusts the time based on the time information in the received signal.
A problem with such radio-controlled timepieces is that depending upon the conditions of the surrounding electrical environment the timepiece may not be able to receive the time signal. Local magnetic fields, for example, could interfere with reception, and reception might not be possible inside some buildings. Reception may also not be possible when travelling abroad, or simply when in areas outside the range of the standard time signal transmitter.
Even if the automatic reception function operates under such circumstances the timepiece will be unable to receive the signal and the time will not be adjusted.
Attempting reception despite being unable to receive the signal needlessly consumes power. This reception operation is the most power-consuming operation of the timepiece, and in a battery-powered timepiece such as a wristwatch, results in a shortened battery life.